1. Field Of The Invention
The invention relates to a method of sewing a flap to a workpiece and to an automatic sewing device to put this method into practice.
2. Background Art
A device of a sewing machine is known from U.S. Pat. No. 4,281,606 for placing a flap or the like from an insertion station on to a workpiece in a holding position. In this case a flap clamp is provided on a workpiece clamp or a workpiece holder, respectively. Further, an inclined plate is provided, on which the flap can be oriented such that it projects with a marginal portion towards the workpiece holder and beyond the plate. Further, a clamping clasp is provided, by means of which the projecting marginal portion of the flap can be seized. The clamping clasp together with the flap is then drawn through between a clamping lever associated with the workpiece holder and the upper side of the workpiece holder, after which it is placed on to the workpiece. The method herein applied is extraordinarily time-consuming. Moreover, the constructional expenditure for the device is considerable. The positional accuracy of the flap on the workpiece is ensured only within certain limits.
From the PFAFF information brochure, "PFAFF 310-01 Special Service" (imprint no. 296-12-15815), it is known to sew a pocket on a workpiece by a corresponding seam as a first step. Then a flap is positioned and sewn on. This method, too, is time-consuming, the sewing on of the pocket and the positioning of the flap relative to the workpiece and the sewing on of the flap taking place in individual, separate operating cycles.